CVE-2021-41186: ReDoS vulnerability in parser_apache2
First published: Fri Oct 29 2021(Updated: )
Fluentd collects events from various data sources and writes them to files to help unify logging infrastructure. The parser_apache2 plugin in Fluentd v0.14.14 to v1.14.1 suffers from a regular expression denial of service (ReDoS) vulnerability. A broken apache log with a certain pattern of string can spend too much time in a regular expression, resulting in the potential for a DoS attack. This issue is patched in version 1.14.2 There are two workarounds available. Either don't use parser_apache2 for parsing logs (which cannot guarantee generated by Apache), or put patched version of parser_apache2.rb into /etc/fluent/plugin directory (or any other directories specified by the environment variable `FLUENT_PLUGIN` or `--plugin` option of fluentd).
Credit: security-advisories@github.com security-advisories@github.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Cogent Datahub | >=0.14.14<=1.14.1 |
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2021-41186?
CVE-2021-41186 has a medium severity rating due to its potential to cause denial of service.
How do I fix CVE-2021-41186?
To fix CVE-2021-41186, you should upgrade Fluentd to a version later than 1.14.1.
What specific versions of Fluentd are affected by CVE-2021-41186?
CVE-2021-41186 affects Fluentd versions from 0.14.14 to 1.14.1.
What is the nature of the vulnerability in CVE-2021-41186?
The vulnerability in CVE-2021-41186 is a regular expression denial of service (ReDoS) caused by a broken apache log.
What components are impacted by CVE-2021-41186?
CVE-2021-41186 specifically impacts the parser_apache2 plugin in Fluentd.
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